The long-term goal of the research performed in this lab is to gain an understanding of the role of genes in development. Toward this end we have performed: genetic, developmental and molecular analyses of a. group of homoeotic genes in Drosophila melanogaster. These genes which are members of a group of tightly linked loci called the Antennapedia Complex (ANT-C) cause transformations in portions of the animal. Mutations in four of the loci Sex combs reduced, Deformed proboscipedia and labial have shown that these genes function in the specification of the mouthpart (gnathocephalic) and most anterior thoracic segment. We have cloned the four genes and determined the spatial and temporal distribution of the gene products. We wish to now understand more fully the manner in which these genes are regulated temporally and spatially. In order to accomplish this we will perform a series of combined genetic and molecular investigations utilizing the reagents developed in prior experimentation. The distribution of the gene products of the four loci will be determined by immuno staining embryos carrying mutations as well as lesions in homoeotic loci and the genes thought to regulate the homoeotics. We will also doubly stain wild type and mutation bearing animals using pair-wise combinations of the antisera. This should reveal any "regulatory" interactions among the various loci. Intronless minigenes will be constructed and cosmid clones carrying each locus will be recovered. These will be returned to the genome via P- element mediated transformation. The ability of these constructs to affect development in both euploid and hyperploid conditions will be determined. The promotor elements of all four loci will be fused to a reporter gene (lacZ) and analyzed in vivo after transformation. Once a promotor is defined these will be exchanged among the genes and returned to the genome. Such transgenic animals will be used to assess the affects of specific ectopic expression for each of the genes. The protein products of each of the genes will be synthesize and used in binding assays to the promoters of all four genes. Finally we will continue to screen for new mutations in the ANT-C and subject them to the types of analysis outlined above.